This post will be a bit different from others. I brought on Katie Sawvell, a biology major from Northern Kentucky University in order to help me better understand the mechanisms of everything discussed. Katie’s contributions will be in orange while mine will be in blue.
DISCLAIMER: We are NOT nutrition experts. You should talk to your doctor before making extreme diet changes (but educate yourself above all-else) and DON’T do this if you’re under 18. Many of the studies we look at applied alternate-day-fasting, Ramadan fasting, fasting-mimicking diets, or prolonged fasting, though some did use OMAD. The mechanisms involved are mostly the same, so outcomes can be generalized to some degree.
How We Started
Remember how in my Minimalism post I described the routine I developed upon starting the blog: wake up, coffee shop to research and write, gym, work? Well in the course of writing at a local coffee shop I met Katie when she allowed me to use her wifi hotspot.
I had seen her in said coffee shop for about three days in a row prior to showing up one Saturday not knowing the shop deactivates their wifi on Saturdays in order to encourage people to talk to one another – I guess it worked.
We got to talking and inevitably I brought up the fact that I eat once a day to which I received a (standard) appalled look. But rather than the typical “are you simple or something?” that accompanies that look, she told me she also eats one meal a day and was surprised to find someone else who does. I was just as shocked.
At this point she’d also heard about my blog and with her being a bio major and general science enthusiast, she asked if she could collaborate with me on my one meal a day (OMAD) post-in-progress. Now, not to shake your faith in my ability, but the OMAD post was giving me some trouble.
A lot of my time spent on it that far had been defining terms and understanding the fundamentals of metabolism; so having someone to help who knows more about my own diet than I do has expedited things (and damaged my ego to some degree).
Jake’s and my OMAD journeys began very differently. I spent most of 2018 completing a genetics research internship and semester in France. It is a bit ironic that I began OMAD in France since the French adhere religiously to the three-meals-a-day paradigm. In France, the days are structured around these three meals, none more important than another, with lunch and dinner lasting at least one hour.
My days, on the other hand, were structured entirely around classes and research. I didn’t have time to stop to eat and often preferred working through the lunch hour when the lab was empty. By the time I got back to the dorms each night, the communal kitchens were packed, and there was no point trying to cook in all that chaos.
Refusing to spend a fortune at French restaurants or to survive off junk food, I became a true sandwich connoisseur, masterfully crafting a baguette-based variation each night.
So, unlike Jake, I did not actively decide to eat once a day, I sort of passively slipped into the habit. Despite that, we have both seen incredible results.
I didn’t begin with OMAD, however. I first decided to give fasting a go this past summer well before I had started doing research-based deep dives into my interests with this blog.
After hearing about how fasting expedited weight loss while maintaining or even building muscle, improved immune function, increased lifespan, boosted mental performance, and any number of other benefits from a multitude of YouTube channels as well as a few websites and blogs, I began experimenting with alternate-day-fasting (ADF).
The name pretty well conveys what it is: I eat normally one day, and fast the next. I found that I enjoyed the challenge of abstaining from food and once I had adjusted, doing so wasn’t even a challenge.
Metabolic Machinery
Biology is undoubtedly complicated. Our bodies are continually working to maintain a sort of equilibrium we refer to as homeostasis. Arguably one of the most important and, yes, most complicated processes is metabolism—the breakdown and storage of various energy sources to fuel each individual cell in your body. This process is tightly regulated and entirely dependent on not only what we are consuming but how much and how often we consume.
Insulin and Glucagon are the two main characters of metabolism, and while they are antagonists, they are not enemies. We need both. To put things in the simplest terms: Insulin helps us to use energy as well as store excess while glucagon allows us to break it down later when we need it. Basically, our bodies can be in one of two states: the fed state (absorptive) and the fasted state (postabsorptive).
In the fed state, carbs, specifically glucose (a simple sugar), are the energy source used first by your body once you’ve fed it. Your pancreas secretes insulin to allow glucose in your blood into cells to be used for energy. Any glucose not currently required by your body for energy needs will be stored as glycogen (a chain of glucose) in the liver, and muscle cells.
But our liver and muscle cells can only hold so much glycogen, and before long, our bodies need to find something else to do with that Chinese buffet we’ve devoured. In an effort not to waste any of these precious orange chicken molecules, our body resorts to storing the extra stuff as fat in the adipose tissue (fancy word for fat). It takes about 2-3 hours for your previous meal to be effectively processed and for blood glucose levels to return to normal.
But when the carbs you’ve ingested run out and blood glucose drops, in order to meet energy needs, your body will start to break down that orange chicken glycogen you have stored by secreting glucagon. This is the beginning of the fasted state. After the glycogen is used up too, which takes anywhere from 4-12 hours, fats and proteins are used for energy.
This is where your body starts mining all that golden, high-energy fat hanging over your jeans. The main take-away from this over-simplified explanation is that your body doesn’t actually start burning fat for energy until it has used up all the easy carbohydrate energy you supply it with at each meal.
So, when your body is taking up carbohydrates several times a day, in the form of Chinese buffets or not, there is no need to dig into the fat storage and thus, the muffin top persists.
With this breakdown of fats (known as lipolysis) comes the production of ketone bodies. I’m sure you’ve heard of the ketogenic diet or ketosis, which is founded on the idea of forgoing carbs as much as possible so that your body can jump straight into mining that muffin top gold.
I used ketosis about 6 years ago to lose around 70 pounds in a matter of about 5 months. Fasting works so well because it induces a ketogenic state daily by giving your body ample time between surges of eaten glucose that take your body away from burning into your fat stores.
Muscles without Meals
Now for any of you that have been concerned with losing fat, building muscle, or both, you’ve no doubt heard that you can’t build muscle AND lose fat at the same time. You’ve also likely heard that when you endeavor to lose fat, you’ll end up losing some muscle in the process.
The reason that gaining muscle while losing fat is supposedly impossible is that in order to build muscle, you must have a positive energy balance – more energy being consumed than being used – while losing fat requires just the opposite.
An example of this effect is the study by Moro et al. (2016) following resistance-training athletes showed that an intermittent fasting (IF) schedule where the athletes only consumed calories during an 8 hour window resulted in fat loss without loss of muscle tone.
The athletes didn’t just maintain muscle mass, but were able to gain muscle over the course of the study. OMAD could be considered a more intense form of IF as the fasting period is often prolonged and the eating period only lasts 1-2 hours.
The major reason fasting is proposed to allow the seeming anomaly of simultaneous fat loss and muscle gain to take place is twofold: because of alternating stages of large calorie surplus followed by extended periods of calorie deficit with increased concentrations of every bodybuilder’s best friend – human growth hormone (HGH) while in a fasted state. HGH is associated with increased muscle mass as well as lower body fat in adults.
If I’ve learned anything from this blog, it is that the science on something is almost never as cut and dry as YouTube channels, blogs, and even the news will have you believe. A precursory study on fasting and HGH by Ho et al. from 1988 found that the typical pulses of HGH secretion are amplified in volume and occur with higher frequency when a person fasts.
Further, many studies report that a protein known as insulin-like growth factor 1 (IGF-1), which mediates HGH release, is lowered in fasting individuals. Essentially IGF-1 inhibits the hormone which triggers (there’s always a goddamn extra step with this stuff) the release of HGH.
Well all right, you might say, more HGH, more muscle, more “hell yeah!” But a study on mice by Inagaki et al. found that fasting produces a hormonal environment which makes your body more resistant to HGH’s effects. So it would seem that fasting does boost your HGH levels, but its effects may be blunted by other accompanying hormonal changes.
Or perhaps the HGH boosts outweigh the effects of increased resistance. We can’t say for sure, so in this case, I’ll just remark that, anecdotally, I’ve seen some significant muscle gains since beginning OMAD that I can’t attribute to changes in my workout routine.
But Aren’t You Hungry?
Something which undoubtedly made it easier to notice these gains was dropping off some of the fat that keto and I didn’t get to. I have struggled for years trying to finish off the fat left over from by gluttonous childhood since my initial weight loss endeavor. I’ve since eaten healthily, but I need to eat a lot to feel satiated, and I like to eat often.
I always thought that this frequent need for food was just a remnant of the poor metabolism I built on a balanced foundation of hot dogs and mac n’ cheese as a child, but when I was well into ADF I noticed that hunger just didn’t happen on fasting days. I only really thought about food when my friends ate around me, and even then I didn’t particularly want to eat.
When I began OMAD in France, my stomach held a grudge and threw a fit in the afternoons when I didn’t oblige its regular eating schedule, but I had no choice other than to ignore it, and I soon came to realize that the hunger always passed. Your stomach is like a puppy; if you stop feeding it scraps all the time, it will stop begging.
Before long, I noticed my jeans were getting looser, my muffin top was receding, and my emerging cheekbones refined my face. I was a bit worried this weight loss wasn’t healthy, but I haven’t experienced any related health complications since starting and must admit I feel better than ever before.
The reason that your stomach begs like a puppy is due to there being insulin in the blood without enough glucose to match it. Think of insulin as the smell that attracts the puppy into the kitchen.
Rodin explained in her paper from 1985 that insulin spikes when food is seen, smelled, and most importantly, expected. Insulin lowers your blood glucose and consequently triggers a hormonal cascade that makes you hungry so you’ll eat and bring it back up.
So, with the knowledge that insulin spikes when food is expected, around times that you typically eat, insulin will spike and you’ll get ravenously hungry.
This is what I’d say accounts for the diminishing hunger once you eat on some form of IF for about a week. Once your regular expectancy for food leaves, so too will the hunger.
One interesting thing worth noting here is that leptin, the hormone thought to inhibit hunger was found to be lowered during fasting in almost every study we looked at, yet hunger was lower or unaffected in these studies. It’s unclear why this is the case, but it could have to do with alterations in leptin resistance from fasting, though there’s not any literature about this specifically that we could find.
Skipping Breakfast… and Lunch
I didn’t immediately link the benefits to eating once a day; maybe I assumed it was the French air or something. But like Jake, I am a YouTube fiend. Although my videos of choice were less health-focused and much more late-night-comedy-centered, I somehow still managed to come across the video “Longevity & why I now eat one meal a day.”
I thought, “Well, I have been doing that for months now, and I didn’t even know it was, like, a thing??” So, I watched it, and everything seemed to click. The science was solid, it made evolutionary sense, and it explained the changes I had seen in my body devoid of health issues.
Flash forward to my return home. Despite being back in the comfort of my kitchen, with 24-hour supermarket access, I resolutely continued my new lifestyle. After telling a few people and getting less than enthusiastic—and sometimes appalled—reactions, I stopped mentioning it to people, I just did my thing.
Then, I stumbled into this coffee shop blog bum who tells me he also only eats one meal a day? What? It was really encouraging to meet someone who wasn’t repulsed by my skipping of breakfast and lunch, so here I am.
Before I got to OMAD, ADF had worked for my body, but it did not work for my social life. I had missed out on or only half-enjoyed many outings with friends that were food or alcohol-centric. Not ready to go full loner and start a blog, I endeavored to try that diet I’d heard about in the same video Katie mentioned.
I started eating huge bowls from Chipotle on a daily basis around 4 PM. And now I could eat with those friends but make their meal my one meal, with the added social spectacle of consuming around 2,000 calories worth of food.
On OMAD is where I saw the true benefits of fasting. Not only was I losing weight and gaining muscle, but I was saving time and money, haven’t been sick since starting, and as a result of only eating with a truly empty stomach, I never felt the post-lunch lethargy everyone seems to get.
I just felt better and cleaner in general; and eating once a day allowed me to have a primitive, cathartic food binge daily without any of the associated guilt (or love handles) that doing so on a normal eating schedule would entail.
Muffin Top Mining
The weight loss brought by IF is well documented in scientific literature as well. A study by Gnanou et al. from 2015 followed 20 muslim men from the National Defence University of Malaysia during Ramadan in which they fast from dawn until dusk (~12 hours) daily.
These men also ate the same meals and had daily physical training, though their training routine was less strenuous during Ramadan. At the end of the month, subjects had seen a 2.4% reduction in body weight and a 5.5% reduction in Body Mass Index (BMI) on average.
Now you may be tempted to think that the timing has nothing to do with weight-loss, and fasting gives results because people are simply eating less when they fast. However, a 2007 study by Carlson et al. found that IF without caloric restriction also resulted in fat loss, indicating that these fasting periods really are effective, even if caloric consumption is the same.
That being said, IF does usually reduce caloric intake as it is difficult to consume the same number of calories within a short amount of time as you usually would throughout an entire day (but that doesn’t stop me). So, this method increases fat loss by increasing fasting time and decreases fat gain by incidentally reducing caloric intake.
Fasting Fears
If you’re like me, you’re probably concerned at this point that fasting may slow your metabolism or damage your health otherwise. For me these fears were soundly laid to rest when I heard about a 1973 study by Stewart and Fleming in which they followed a 456 pound man who fasted for 382 consecutive days.
The 27 year old man, Angus Barbieri, went over a year subsisting on nothing but water, coffee, tea, multivitamins and supplements. He reduced his weight to 180 pounds by the end of the fast and was only 196 pounds when he checked in 5 years following the study. Barbieri was no worse for wear after the study.
OMAD or TMAD?
But which is better for weight loss? Calorie restriction or fasting? A meta-analysis of very low calorie diet (VLCD) – eating 800 or fewer calories a day – and ADF – in this case consuming 800 or fewer calories on fasting days while eating normally on others – studies sheds some light on this. When compared, both routes proved effective for substantial weight loss, with VLCDs producing somewhat greater weight reduction.
The difference is that studies of ADF reflected less fatigue in maintaining the diet and a lower risk of weight regain. This is particularly impressive when you consider that fasting days were the same as normal days for VLCD participants and ADF participants got to eat normally every other day.
Take-aways
We hope you enjoyed the different style of this post and above all that we properly demonstrated the effects of OMAD and fasting in general. It’s not something meant for everyone, but it can be safe, it can help you achieve and maintain weight loss, and it saves a good deal of thought, time, and money.
If you decide that you want to embark on a fasting diet, make sure you read up on how to do it safely, talk to your doctor, and make sure you’re getting water, nutrients, and electrolytes in the absence of food.
The benefits of fasting don’t stop there, though. There are a plethora of other positive effects including improved cognitive performance, immune function, and increased lifespan which we didn’t have the space to mention in this post. In order to give them proper investigation there will be another post like this coming soon!
References
- Alhamdan, B. A., Garcia‐Alvarez, A., Alzahrnai, A. H., Karanxha, J., Stretchberry, D. R., Contrera, K. J., … Cheskin, L. J. (2016). Alternate-day versus daily energy restriction diets: which is more effective for weight loss? A systematic review and meta-analysis. Obesity Science & Practice, 2(3), 293–302. https://doi.org/10.1002/osp4.52
- Antoni, R., Johnston, K. L., Collins, A. L., & Robertson, M. D. (2017). Effects of intermittent fasting on glucose and lipid metabolism. Proceedings of the Nutrition Society, 76(03), 361–368. https://doi.org/10.1017/S0029665116002986
- Carlson, O., Martin, B., Stote, K. S., Golden, E., Maudsley, S., Najjar, S. S., Mattson, M. P. (2007). Impact of reduced meal frequency without caloric restriction on glucose regulation in healthy, normal-weight middle-aged men and women. Metabolism, 56, 1729–1734. https://doi.org/10.1016/j.metabol.2007.07.018
- Gnanou, J. V., Caszo, B. A., Khalil, K. M., Abdullah, S. L., Knight, V. F., & Bidin, M. Z. (2015). Effects of Ramadan fasting on glucose homeostasis and adiponectin levels in healthy adult males. Journal of Diabetes & Metabolic Disorders, 14(1). https://doi.org/10.1186/s40200-015-0183-9
- Ho, K. Y., Veldhuis, J. D., Johnson, M. L., Furlanetto, R., Evans, W. S., Alberti, K. G., & Thorner, M. O. (1988). Fasting enhances growth hormone secretion and amplifies the complex rhythms of growth hormone secretion in man. Journal of Clinical Investigation, 81(4), 968–975. https://doi.org/10.1172/JCI113450
- Horne, B. D., Muhlestein, J. B., Lappé, D. L., May, H. T., Carlquist, J. F., Galenko, O., Anderson, J. L. (2013). Randomized cross-over trial of short-term water-only fasting: Metabolic and cardiovascular consequences. Nutrition, Metabolism and Cardiovascular Diseases, 23(11), 1050–1057. https://doi.org/10.1016/j.numecd.2012.09.007
- Inagaki, T., Lin, V. Y., Goetz, R., Mohammadi, M., Mangelsdorf, D. J., & Kliewer, S. A. (2008). Inhibition of growth hormone signaling by the fasting-induced hormone FGF21. Cell Metabolism, 8(1), 77-83. doi:10.1016/j.cmet.2008.05.006
- LeCheminant, J. D., Christenson, E., Bailey, B. W., & Tucker, L. A. (2013). Restricting night-time eating reduces daily energy intake in healthy young men: a short-term cross-over study. British Journal of Nutrition, 110(11), 2108–2113. https://doi.org/10.1017/S0007114513001359
- Longo, V. D., & Mattson, M. P. (2014). Fasting: molecular mechanisms and clinical applications. Cell Metabolism, 19(2), 181–192. https://doi.org/10.1016/j.cmet.2013.12.008
- Mattson, M. P., Allison, D. B., Fontana, L., Harvie, M., Longo, V. D., Malaisse, W. J., Panda, S. (2014). Meal frequency and timing in health and disease. Proceedings of the National Academy of Sciences of the United States of America, 111(47), 16647–16653.
- Maideen, N. M. P., Jumale, A., Alatrash, J. I. H., Sukkur, A. A. A. (2018). Health benefits of Islamic intermittent fasting. Journal of Fasting and Health, 5(4), 162-171.
- Moro, T., Tinsley, G., Bianco, A., Marcolin, G., Pacelli, Q. F., Battaglia, G., Paoli, A. (2016). Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males. Journal of Translational Medicine, 14(1), 290. https://doi.org/10.1186/s12967-016-1044-0
- Rodin, J. (1985). Insulin levels, hunger, and food intake: An example of feedback loops in body weight regulation. Health Psychology, 4(1), 1-24. doi:10.1037/0278-6133.4.1.1
- Stewart, W. K., & Fleming, L. W. (1973). Features of a successful therapeutic fast of 382 days’ duration. Postgraduate Medical Journal, 49(569), 203–209.
- https://www.mayoclinic.org/healthy-lifestyle/healthy-aging/in-depth/growth-hormone/art-20045735
- https://www.youtube.com/watch?v=PKfR6bAXr-c&t=
- https://www.youtube.com/watch?v=4UkZAwKoCP8&t=
- https://www.youtube.com/watch?v=kb146Y1igTQ&t=4s